----- Original Message -----
From: "Kok Chen" <chen@mac.com>
To: "John Fleming" <john@wa9als.com>
Cc: <rtty@contesting.com>
Sent: Tuesday, July 13, 2004 2:54 PM
Subject: Re: [RTTY] Yaesu FT-920 setup - HELP!!
>
> On Jul 13, 2004, at 12:36 PM, John Fleming wrote:
>
> > Kyle, if you're using a BUXCOMM interface that utilizes a 4N25 or
> > similar
> > optoisolator, I'm not a bit surprised it won't key as expected. Do
> > youself
> > a favor - Make a plug for your rig's FSK ACC connector with a wire
> > coming
> > out for ground and FSK SHIFT. With the rig in RTTY mode, put it in
> > transmit
> > manually and then short the wires together intermittently and see if
> > you get
> > the expected tone shifts. If so, and I believe you will, then it
> > proves the
> > 4N25 interface will not key the Yaesu. It may appear to short using a
> > VOM,
> > but it's actually not low enough to key the stubborn Yaesus. If it
> > doesn't
> > key manually, then there's some other problem with the rig itself.
> > Let us
> > know what happens. This has been documented somewhat by more than one
> > of us
> > previously. Maybe W7AY would care to comment?
>
> Hah, you'd read my mind, John. I had just 10 minutes ago sent Kyle a
> private email suggesting that he monitor the rig while grounding and
> ungrounding the SHIFT key in the 4-pin DIN connector (I assume the
> connector is the same one used on my FT-990 and FT-1000MP) to first
> make sure his rig is set up correctly. (Yeah, I did mention a dummy
> load, HI.)
>
> I then mentioned to Kyle that a Darlington transistor would not be able
> to drive a Yaesu. I have no idea what a Buxcomm is, though. Does it
> use a optoisolator with a Darlington output? A normal optoisolator
> should work if you hit the LED with a large enough current, but
> probably not from the wimpy RS-232c signals.
>
> 73
> Chen, W7AY
I don't know exactly what he has, but I'm sure it's based on a 4N25 opto.
See
http://www.k4abt.com/psk31parts.htm
for examples. - John
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